This invention relates generally to semiconductor fabrication and more specifically to forming an interconnect of a semiconductor device.
Metals such as copper are typically used as interconnect material for ultra-large scale integrated circuits (ULSICs), microelectronics, opto-electronics, and other electronic devices. Known etching techniques for forming metal interconnects, however, have disadvantages. Some of the etching techniques result in poor etch uniformity or require the use of complex systems or processes. Consequently, forming metal interconnects for electronic devices has posed problems.
In accordance with the present invention, disadvantages and problems associated with previous techniques for forming an interconnect of a semiconductor device may be reduced or eliminated.
According to one embodiment of the present invention, forming an interconnect of a semiconductor device includes defining a recessed structure proximate to an outer surface of a substrate of a semiconductor device. A metal layer is deposited within the recessed structure. A region of the metal layer is exposed to a plasma operable to react with the region of the metal layer. A metal compound layer is formed from the region of the metal layer by reacting the region of the metal layer with the plasma. The metal compound layer is removed from the semiconductor structure to yield a remaining metal layer. An interconnect of the semiconductor device is formed from the remaining metal layer.
Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may be that metal is removed by exposing the metal to a plasma to form a metal compound. The metal compound may be effectively removed by an acid or base solution or by heating. Another technical advantage of one embodiment may be that the metal removal is highly selective. Typically, the acid or base solution or heating removes only the metal that has been transformed into the metal compound. Another technical advantage of one embodiment may be that the removal of metal may be performed using a conventional plasma reactor, and thus does not require building new equipment.